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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 78 (1956), S. 725-728 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 3 (2000), S. 377-388 
    ISSN: 1292-895X
    Keywords: PACS. 61.30.Jf defects in liquid crystals - 64.70.Md Transitions in liquid crystals - 87.16.Dg Membranes, bilayers, and vesicles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: A lyotropic system, consisting of a lecithin (DMPC) and a non-ionic surfactant (C12E5) in water was studied. The system exhibits a lamellar-to-nematic phase transition. The nematic phase appears as the temperature is decreased and only exists in a very limited temperature and concentration range, for specific lipid-to-surfactant ratios. While a lamellar phase is found at higher temperatures in both mixed and pure C12E5 systems, the transition to the nematic phase at lower temperatures coincides with a micellar phase in the pure C12E5 system. The transition appears to be driven by the strong temperature dependence of the surfactant film spontaneous curvature. The structural properties of the lamellar phase close to the lamellar-to-nematic boundary have been studied by polarised light microscopy and small-angle neutron and X-ray scattering experiments. The signature of a helical defect with Burgers vector of magnitude 2 is apparent in our data, close to the lamellar-to-nematic phase transition. The proliferation of screw dislocations in the lamellar phase might be a plausible mechanism for driving this transition.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 53 (1975), S. 385-389 
    ISSN: 1432-1440
    Keywords: Coronary heart disease ; myocardial infarction ; risk factors ; erythrocyte aggregation ; cell volume distribution ; Koronare Herzkrankheit ; Herzinfarkt ; Risikofaktoren ; Erythrocytenaggregation ; Erythrocytenvolumenverteilung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung 1. Die in-vitro-Messung der Erythrocytenaggregation wurde so verbessert, daß der Variationskoeffizient auf ±14,2% herabgedrückt wurde. 2. Mit der verbesserten Methode konnten die früheren Befunde statistisch hochsignifikant gesichert werden, daß sonst gesunde starke Raucher einen wesentlichen höheren Erythrocytenaggregationswert aufweisen als Nichtraucher. 3. Es wurde auch bei anderen Risikofaktoren koronarer Herzerkrankungen nachgewiesen, daß sie zu einer Erhöhung des Aggregationswerts der Erythrocyten führen. Insbesondere konnte dies bei Hypercholesterinämie nachgewiesen werden. 4. Mehrere Risikofaktoren beim gleichen Patienten bewirken einen überadditiv hohen Aggregationswert der Erythrocyten.
    Notes: Summary 1. The vitro test for red blood cell aggregation has been improved, the coefficient of variation was decreased to 14.2. 2. By the improved method the earlier findings were confirmed with high statistical significance that heavy smokers have a significantly higher red blood cell aggregation value in comparison with nonsmokers. 3. It could be shown that other coronary risk factors, especially hypercholesterolaemia, increase the aggregation value too. 4. The aggregation of red blood cells increases in the presence of several coronary risk factors in the same patient to higher values than expected from the addition of the aggregations caused by single risk factors.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1238
    Keywords: Nitric oxide ; Persistent pulmonary hypertension ; Extracorporeal membrane oxygenation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Inhaled nitric oxide (NO) is thought to provide a noninvasive therapeutic alternative to extracorporeal membrane oxygenation (ECMO) in the treatment of persistent pulmonary hypertension of the newborn (PPHN). Objective Since January 1993, we have studied inhalation of NO in PPHN patients meeting the ECMO criteria of our institution. We focused on the questions of whether or not the need for ECMO could be obviated and whether differences could be found between NO responders and nonresponders. Design NO gas was delivered via conventional IPPV ventilation in incrementally increasing concentrations from 20 to 80 ppm. Patients NO therapy was attempted in ten ECMO candidates with clinical and echocardiographical evidence of PPHN (mean OI 51.9, SD 10.4). Results At various NO levels (30–60 ppm), five patients showed a significant increase in meanPaO2 (range 32.9–85.9 mmHg). Improvement was transient in three patients (6–10 h) and prolonged in two others (54–80 h); in the latter cases, ECMO was avoided. Five patients did not respond at all to treatment. Responders and nonresponders differed in their mean respiratory tidal volume (8.9 vs 4.18 ml/kg,P〈0.05). Conclusions In our study, inhalation of NO obviated the necessity of ECMO therapy in only two out of ten PPHN patients. Thus, we would discourage any overoptimistic expectations about the effectiveness of NO therapy in PPHN until larger clinical trials have been performed.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1076
    Keywords: Key words Head trauma  ;  Glasgow Outcome Scale  ;   Neuropsychological tests  ;  Magnetic resonance imaging  ;  Long-term follow up
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The primary issues addressed in this study were: (1) determination of the significance of the classification “good outcome” utilizing the Glasgow Outcome Scale (GOS) in children at least 1 year after brain injury; (2) detection of residual lesions of brain parenchyma in these children upon follow up MRI scans; and (3) detection of relationships between neuropsychological test performance and MRI results. Selection criteria included children 6–15 years of age at the time of testing who received an initial CT scan at the time of their head injury and who had been injured at least 12 months prior to the follow up test. Only children who did not demonstrate neurological disability at the time of follow up examination were selected. The children showed a status of “good outcome” as defined by the GOS. Neurological examination, neuropsychological tests and an MRI were done. The test results of 59 patients were compared to those of a matched control group. Children, after receiving head injuries, showed significantly poorer results with respect to cognitive, motor and fine motor skills. Of all MRI-scans 66% revealed pathological findings. Cortical lesions were detected on MRI in 14% of cases; subcortical injuries were detected in 12% and, deep white matter lesions in 31%. Furthermore, corpus callosum damage was observed in 26% of cases. Pathological MRI findings were also observed in children with mild head injuries. All of the children with normal MRI findings showed abilities comparable to those of children in the control group. Patients with cortical lesions exhibited only motor deficits, whereas motor and cognitive deficits were seen in patients with deep white matter lesions. Children with multiple lesions demonstrated test results in all variables 1 to 2 standard deviations below those of the control group. Conclusions Children suffering a brain injury who 1 year later are classified within the “good outcome” group according to the Glasgow Outcome Scale often have significant morphological and functional brain deficits.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1076
    Keywords: Neonatal stroke ; Magnetic resonance imaging ; Magnetic resonance angiography ; Neuropsychological tests ; Long-term follow up
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We describe the long-term follow up of infants after neonatal stroke of the middle cerebral artery (MCA). Stroke was diagnosed by CT scan in eight full-term neonates. Three dimensional (volume) magnetic resonance angiography (MRA) is a noninvasive technique that images the arterial vessels without contrast agents. All patients, aged from 1.5 to 8.4 years, were investigated by MRI and MRA and by neuropsychological tests. Cognitive development was investigated by intelligence tests, tests of visual perception, motor and language development. Out of the eight patients, seven had a retarded mental and motor development, and 50% of the children were treated for epilepsy. Seven patients had a spastic hemiparesis. Seven out of eight children showed major cognitive deficits. In all patients, MRI revealed clear parenchymal defects with variable distribution patterns. MRA studies showed abnormalities corresponding to the expected vascular distribution. Children with complications at delivery, with seizures, and an interruption of the main stem of MCA as demonstrated on MRA had the least favourable long-term follow up prognosis with severe cognitive delays.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    European journal of pediatrics 128 (1978), S. 187-195 
    ISSN: 1432-1076
    Keywords: Insulin ; Glucagon ; Glucose ; Free fatty acids ; Newborn infant ; Cord blood ; Arterio-venous difference
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Bei Geburt ist der Blutzucker bei der Mutter am höchsten, niedriger in der Nabelvene und am tiefsten in der Nabelarterie. Diese Unterschiede sind statistisch signifikant. Auch die Konzentration der freien Fettsäuren (FFS) weist ein Konzentrationsgefälle von der Mutter über die Nabelvene zur Nabelarterie auf. Diese Resultate unterstützen die Annahme, daß Glucose und FFS von der Mutter via Placenta auf den Fötus übergehen. Im mütterlichen Blut ist die Insulinkonzentration höher als im Nabelschnurblut. Es ist kein eindeutiger Unterschied zwischen Nabelvene und-arterie vorhanden. Nur im mütterlichen Blut ist eine signifikante Korrelation zwischen Glucose und Insulin nachweisbar. Hinsichtlich der Glucagonkonzentration bestehen nur geringe Unterschiede zwischen dem mütterlichen Blut und der Nabelarterie. Sie ist aber in der Nabelvene signifikant höher als bei der Mutter. Das Verhalten von Insulin und Glucagon ist vereinbar mit der Annahme, daß diese Hormone die Placenta nicht in wesentlichem Ausmaß passieren und im Fötus gebildet werden. In den ersten Stunden nach der Geburt sinkt die Glucose, die FFS steigen an, Insulin sinkt ab, und es erfolgt ein wesentlicher Anstieg von Glucagon.
    Notes: Abstract At birth there is a statistically significant correlation between the maternal blood sugar and the umbilical venous and arterial blood glucose. The glucose concentration in the mother is higher than in the umbilical vein, and in the latter higher than in the umbilical artery. The free fatty acids also show a falling gradient from the mother to the umbilical vein and artery. This supports the assumption that glucose and FFA pass the placenta from the mother to the foetus. Insulin concentration is significantly higher in the mother than in the cord blood. There is however no difference between umbilical venous and arterial plasma insulin. A statistically significant correlation between glucose and insulin is only demonstrable in the maternal blood. Glucagon levels are about the same in maternal and umbilical arterial blood, but are significantly higher in umbilical venous blood. These results are consistent with the supposition that insulin and glucagon do not cross the placenta to a significant extent and can be synthesised by the foetus. In the first few hours after birth, a fall of glucose and a rise in FFA occur at the same time. Insulin tends to be lower than at birth and glucagon rises.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Il nuovo cimento della Società Italiana di Fisica 16 (1994), S. 1585-1594 
    ISSN: 0392-6737
    Keywords: Molecular biophysics ; Defects in liquid crystals ; Conference proceedings
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary The effect of adding the defect-forming molecules melittin and C12E5 to DMPC membranes has been studied and the corresponding phase diagrams established. Light, X-ray and neutron small-angle scattering have been used to characterize the mixed membranes. Both systems show a melting of the lamellar Lα into an isotropic phase upon addition of the second membrane constituent. The molar ratio, where the melting occurs is the same in concentrated and dilute samples. For the DMPC/C12E5 system not only membrane composition, but also temperature can be used to induce a transition from an isotropic to a lamellar phase.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1600-0625
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The availability of neuropeptides or neuroendocrine hormones as important modulators of innate and adaptive immune responses is effectively controlled by neuropeptide-specific peptidases. In previous studies, drug inhibition or genomic deletion of neutral endopeptidase (NEP, CD10) or of angiotensin-converting enzyme (ACE, CD143) resulted in a profound augmentation of murine allergic contact dermatitis responses. Likewise, we have identified dermal microvascular endothelial cells (EC) as both source and target of the proopiomelanocortin (POMC) peptides ACTH and α-melanocyte-stimulating hormone (α-MSH), in particular. EC express melanocortin receptor (MC-) 1 and α-MSH is capable of profoundly downregulating LPS- or cytokine-induced expression of adhesion molecules in vitro and of endotoxin-induced cutaneous vasculitis in vivo. In this study, we have tested the hypothesis that NEP or ACE expressed by EC may influence the local bioavailability of POMC peptides. Cell membranes prepared from the high NEP/low ACE expressing human microvascular endothelial cell line 1 (HMEC-1) or from low NEP/high ACE expressing primary human dermal EC (HDMEC) were incubated for 30–480 min with ACTH1–39 in the presence or absence of NEP or ACE inhibitors, respectively. Analysis of membrane supernatants for ACTH and α-MSH by radioimmunoassay revealed a decrease in ACTH immunoreactivity (IR) over time that could be partially blocked with NEP inhibitors. In parallel, α-MSH IR increased peaking after 60 min. Fragments generated by incubation of HMEC-1 or HDMEC membranes with ACTH1–39, ACHT1–24 or α-MSH for 1–120 min were further analyzed by Matrix-assisted-LASER desorption time-of-flight (MALDI-TOF) spectroscopy. HMEC-1 membranes generated main peptide products with molecular masses of 2007, 1057 and 945, respectively, from ACTH1–39, and 1057 from ACTH1–24. Inhibition with NEP, but not ACE inhibitors altered the fragmentation profile indicating that NEP is involved in degradation of both ACTH1–39 and ACTH1–24. Likewise, HDMEC membranes fragmented ACTH similar to HMEC-1 membranes in the presence of NEP inhibitors. Both HMEC-1 and HDMEC membranes were also capable of slowly degrading α-MSH suggesting that EC proteolytic peptidases are important for the local control of ACTH/α-MSH bioavailability, which may play a significant role in controlling local cutaneous inflammatory responses.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 100 (1994), S. 3307-3316 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The dynamics of water between highly oriented multilayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) has been studied in two time domains at different hydration levels. Incoherent quasielastic neutron scattering (QENS) and deuterium-nuclear magnetic resonance (NMR) longitudinal (T1) relaxation were employed to investigate both the high-frequency motions of water (10−9–10−11 s time scale) and their anisotropy, while 2H-NMR transverse (T2) relaxation was used for obtaining information on low frequency dynamical processes (microsecond time scale). Our results show that high frequency dynamics (picosecond-time scale) at low hydration (three to four water molecules per lipid) can be understood solely as a uniaxial rotation of the water molecules tightly bound to DPPC head groups with a correlation time τrot≈62 ps at 55 °C and a rotational radius of 1±0.1 A(ring), but with no detectable translational degrees of freedom. The 2H-NMR T1 data (nanosecond-time scale) can be explained satisfactorily on the basis of fast rotations with the correlation time above and a slower reorientation of the rotational axis (correlation time τ1≈6 ns).Both QENS and 2H-NMR T1 measurements provide an apparent activation energy of Ea=32±1.0 kJ/mol for this process. Increasing the hydration level of the multilayers leaves the rotational motion essentially unchanged, but enables additional translational motion which can be considered as a jump diffusion process (diffusion coefficient D=16±1×10−10 m2/s at 44 °C and a mean residence time of τ0=2.0±0.5 ps) of nonbound water. It is interesting to note that this diffusion is completely isotropic on the characteristic length scale of this QENS experiment (≤10 A(ring)). Temperature variation shows that the phase state of the lipids has no significant effect on the high frequency dynamics of the water molecules. Measurements of the 2H-NMR quadrupolar splitting of water (D2O) at temperatures around the phase transition temperature Tm of the oriented DPPC multilayers clearly show a coexistence of the crystalline Lβ' phase and of the fluid Lα phase over a range of up to 4 °C at both sides of Tm. The intermediate Pβ' ("ripple'') phase is suppressed as we worked at hydration levels below saturation. In the coexistence range, exchange of water takes place between crystalline and fluid lipid domains due to water diffusion. This exchange causes a pronounced minimum of the 2H-NMR transverse relaxation time T2 at Tm since this low frequency process satisfies approximately a critical damping condition for a two-site chemical exchange process.
    Type of Medium: Electronic Resource
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